Cylinder grinder



July 26, 1938. R. c. BENNER ET AL Y 2,125,06F

CYLINDER GRINDER Filed Nov. 1e; 1934 Y INVENTOR.

RAYMOND C. BENNER RONHE L. MELTQN ATTORNEY.

Patented July 26,v 1938' FFME CYLINDER campen Raymond C. Benner and Ronnie L. Melton, Niagara Falls, N. Y., assignors, by mesne assignments, to The Carborundum Company, Niagara Falls, N. Y., a corporation of Delaware Application November 16, 1934, Serial No. 753,261

3 Claims. (Cl. 5ll4.3)

This invention relates to the mounting 'of abrasive elements intended for honing or grinding internal cylindrical surfaces such as the cylinders of internal combustion engines. More particularly, this invention relates to an abrasive and carrier assembly in which the abrasive element is secured to a plate member and attached to a supporting base member in such a manner that practically the entire abrasive stone can be utilized for grinding purposes and worn away by abradant action.

The present application is a continuation in part of a copending application Serial No. 585,675, filed January 9, 1932. This prior application de- 1.-, scribes at some length a form of cylinder grinder which is adapted to support and rotate a plurality of abrasive stones. Each abrasive stone is mounted on a carrier whose position can be regulated to adjust the effective operating diameter of the stone and to makeother adjustments which will be briefly described below in order to make clear the kind of work our improvedv mounted stones have to perform.

The above described and other valuable features and advantages of our invention will be understood by reference to the accompanying drawing, wherein like reference numerals are applied. to the corresponding parts in the several views.

Figure l is an elevation partly in section o. a cylinder grinder in which our mounted stones may be used;

Figure 2 is a side elevation of an abrasive stone mounted in accordance with our invention;

Figure 3 is an end View of the mounted stone shown in Figure 2.

Referring to the drawing in detail the reference character l indicates a body member which is of general cylindrical form and which is adapted to support and provide bearings for the several movable parts of the completed grinder. The body i is of a size and of suitable diameter to allow of its being received bodily within the cylindrical bore to be acted upon. The body cated by an operating shaft (not shown) having to be engaged by the driving-pin of a suitable driving shaft which is not shown.

Abrasive carriers 'l are arranged in each of a plurality of bearing apertures 6 for expanding ment t.

member l is adapted to be rotated and recipro movement in a. radially outward direction and for a tilting movement determined by the sliding of the curved surfaces i9. and 20 on the surfaces of the disks il and i8 respectively. Clearance is provided at both ends of the bearing apertures d to permit the abrasive carrier l to tilt to the required extent. Each'carrier l is composed of a fiat plate member la having the above mentioned curved surfaces i9 and 2li, as well as 'enlarged portion lb adapted to support an abrasive ele- The abrasive element 8 is composed, for example, of bonded silicon carbide or of bonded fused alumina and is attached to a plate backing 9 by means'of a layer of cement ld. The plate backing il for the stone may be attached to the abrasive carrier 'l by any convenient means such as screws l2, which are shown in the cut away section of the stone carrier illustrated in Figure 1.

in order to move the carriers 'l radially outward there is provided a sleeve 2t which is rotatably mounted on the driving head 5. Relative axial movement bf these two members 28 and 5 is prevented by the screw stud 2l which projects into an annular groove in the head 5. The sleeve 2li is provided with an internal gear i9 which meshes with an idler gear 3G which is journaled on the screw stud '32. The idler gear 30 meshes in turn with the gear 33 which is rigidly attached to the screw shaft 22 by means of the screw 35. The disks il and lli are engaged respectively by left-hand threaded and right-hand threaded portions of the shaft 22. The disks ll and I8 are slidably mounted on a guide rod (not shown) which is rigidly connected to the casing and which prevents rotation of the disks Il and I8 while permitting their axial movement toward or away from each other. By rotation of the sleeve 28, therefore, the abrasive elements 8 can be moved raidially inward or outward.

The abrasive carriers l are yieldingly held in position during the operation of the grinder by means of garter springs 3l, 38 which t into grooves 39 located near the respective ends of the carriers l.

In .the use of prior types of grinding or honing tools the abrasive elements have been embedded in a self-hardening material or clamped in a channel-shaped metal shield. Approximately one-half of the thickness of the stones has been embedded or clamped in the stone holder and only one-half of the abrasive could be utilized in a useful manner, the remainder being discarded when the holders were refilled. In our improved form of mounting the abrasive stone it may be attached for example in the manner illustrated in Figures 2 and 3, the stone 8 being cemented to a plate backing 9 by means of a layer of cement I0, while the backing 9 is detachably mounted on the enlarged portion 'Ib of the carrier 1. This type of structure permits the entire abrasive stones to be utilized in grinding and eliminates the waste caused by discarding half used stones as is the case with the usual types of mountings. Thus we are able to practically double the useful life of the stones and to reduce the stone cost by approximately one-half,

The backing members 9 can be made of any material having sufficient strength to withstand the stresses encountered in cylinder honing or grinding practice. In certain instances, however, it is desirable to make them of a nickel-steel alloy which has substantially the `same coefficient of expansion as the abrasive. In this case the adherence between the abrasive stone and the metal back is less likely to be disturbed by temperature changes. When the abrasive stone is worn down close to the backing the latter can be discarded or easily returned to the factory and provided with an abrasive stone of full size.

The backing 9 can also be made of a molded composition, containing for example a phenol condensation product resin cured to the so-called C stage in which the molded product reaches its maximum strength and does not soften on application of heat. 'I'his type of molded product can be formed into thin plates in large quantities at low cost. No machining is required in making the backing 9 in the shape shown in Figures 2 and 3 byA means of a moldingvprocess. It is not even necessary to use the layer of cement I0 shown in Figures 2 and 3. The backing can be molded directly onto one-face of the abrasive stone 8-and cured in situ. In attaching the backing directly? a mold of suitable shape is lled, for example, with a molding mixture of suitable character and the abrasive stone is then placed on the mixture with one rectangular face in contact therewith and a pressure of about 500 pounds per square inch is applied. The backing is then cured in situ at a temperature of 30D-350 Fahrenheit.

The backing may also be made by impregnating strips of paper or fabric with phenolic condensation product resin and molding incontact with the stone, followed by curing in the manner described in the preceding paragraph.

The lbacking can also be molded separately from the stone and subsequently cemented thereto, using cements similar to those described below. Various types of cements can be utilized in cementing the abrasive stones to the plate backing. We have found it desirable, however, to employ a cement containing synthetic resin or rubber, which cement is strong enough to withstand the tensile and shearing stresses encountered during grinding and possesses a sufficient degree of resiliency to withstand the vibration and shock of grinding and thermal changes in the process of curing.

While a number of cements are suitable for the present requirements, selection of the particular cement depends upon the type of work for which the abrasives are to be used and the cooling solution or lubricant applied to the abrasive members.

When the device is to be used in wet grinding; that is, where a cooling or lubricating solution such as kerosene 1s used on the abrasive elements. -it is necessary to use a cement which will withstand the chemical action of .said lubricant. Synthetic resin cements to which llers have been added to decrease the coefficient of expansion, have proved successful. `Such a cement may be prepared according to the formula:

560 grams fused quartz (200 mesh and liner), 160 'grams liquid phenolic resin,l cubic centimeters water,

in which the phenolic resin referred to is a liquid A stage phenolic condensation product resin which forms a homogeneous mixture with water.

The plate backings are thoroughly cleaned, as by a sandblast, and the abrasive elements mounted on said backings by a layer of the above mentioned cement. A pressure of approximately five pounds per square inch is applied while the cement is cured for twelve hours at a temperature of 120 C. and for an additional twelvehours at C.

Synthetic resin cements are usually brittle and have a low degree of resiliency. However, we

have found that by using both a fabric material and a synthetic resinous cement between the abrasive element 3 and the plate backing 9, a desired degree of resiliency and resistance to shock may be obtained. In carrying out this method of mounting the abrasive members, the plate backings are cleaned as previously described. Next a layer of a liquid synthetic resin or cement is applied both to the plate backing and the underside of the abrasive element. The fabric material is then placed between the two layers of cement, a pressure of approximately 100 pounds. per square inch applied and the cement cured for one hour at a temperature of 150 C.

In another type of cement which has been used successfully, the binder is a rubber-resin mixture composed of a homogeneous fluid mixture of two parts rubber and one part liquid phenolic resin.

Using the above-described rubber-resin mixture, a suitable cement may be made from the materials given in the following formula:

150 grams rubber-resin mixture. 820 grams silicon carbide grain (320 mesh).

25 grams sulphur.

5 grams iron oxide. cubic centimeters water.

This cement is applied to the previously cleaned plate backing and the abrasive element mounted in position. A pressure of approximately ve pounds per vsquare inch is applied while the cement is cured `for twelve hours at a temperature of C.

From the foregoing description it becomes evident that an abrasive stone attached to a flat backing with the lateral faces of the stone coinpletely exposed and free from support possesess a number of advantages not heretofore obtainable. Since the entire abrasive stone may be utilized for abrading purposes the useful life of the stones is doubled and the stone cost reduced to approximately one-half.

We claim:

1. An abrasive element for a grinding tool comprising an adjustable abrasive carrier, an abrasive Stone, a supporting flat member secured to the back surface only of said abrasive stone by means of. a layer of resilient cement and detachably mounted on said abrasive carrier, the lateral faces of the abrasive stone being completely exposed and free from support..

2. An abrasive article for use incylinder grinding and the like said article comprising a block of bonded abrasive, and a base for said abrasive block, said base being composed'of a metal plate Cil bonded abrasive stick, and a carrier for said abrasive stick detachably connected to said mounting plate, the radially outermost portion of said carrierbeing` between the longitudinal axis of the cylindrical grinder and the innermost face 5 of said abrasive stick.

RAYMOND C.' BENNER. ROMIE L. MELTON. 

